Electronic Journal of Differential Equations (Sep 2014)
Asymptotic behavior of solutions to higher order nonlinear delay differential equations
Abstract
In this article, we study the oscillation and asymptotic behavior of solutions to the nonlinear delay differential equation $$ x^{(n+3)}(t)+p(t)x^{(n)}(t)+q(t)f(x(g(t)))=0. $$ By using a generalized Riccati transformation and an integral averaging technique, we establish sufficient conditions for all solutions to oscillate, or to converge to zero. Especially when the delay has the form $g(t)=at-\tau$, we provide two convenient oscillatory criteria. Some examples are given to illustrate our results.